Axial flow fan and outdoor unit for air conditioner

ABSTRACT

Provided are an axial flow fan and an air conditioner outdoor unit including the axial flow fan. The axial flow fan includes a hub and blades disposed on an outer surface of the hub. Each of the blades satisfies that a shortest distance measured from an imaginary line (L 2 ) passing through a center of the hub to a front end of an outer edge of the blade is greater than a shortest distance measured from the imaginary line (L 2 ) to a rear end of the outer edge of the blade. The front end of the outer edge of the blade is a leading end in a rotation direction of the blade, and the rear end of the outer edge of the blade is a trailing end in the rotation direction of the blade. Owing to the shape of the blade, noise can be reduced while increasing the flowrate of air.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119 and 35U.S.C. 365 to Korean Patent Application No. 10-2010-0138007 (filed onDec. 29, 2010), which is hereby incorporated by reference in itsentirety.

BACKGROUND

The present disclosure relates to an axial flow fan and an airconditioner outdoor unit including the axial flow fan.

Air conditioners are home appliances for cooling and/or heating indoorareas by using refrigerant circulating in heat-exchange cycles. A splittype air conditioner includes an indoor unit and an outdoor unit.Components for heat-exchange cycle such as an outdoor heat exchanger anda compressor are disposed in the outdoor unit.

In addition, a fan is disposed in the outdoor unit to blow air forfacilitating heat exchange between the outdoor heat exchanger andoutdoor air. Generally, an axial flow fan is used as the fan. Air flowsin the direction of a rotation shaft of an axial flow fan.

Hereinafter, an axial flow fan of the related art will be described indetail with reference to the accompanying drawings.

FIG. 1 is a plan view illustrating an axial flow fan 10 of the relatedart, and FIG. 2 is a schematic side view of the axial flow fan 10 of therelated art.

Referring to FIGS. 1 and 2, the axial flow fan 10 includes a hub 11 anda plurality of blades 13. A rotation shaft (not shown) of the axial flowfan 10 is coupled to the hub 11. As the blades 13 are rotated, air isforced to flow.

In detail, based on the rotation direction of the blades 13, the blades13 include: leading edges 14; trailing edges 15; and tips 16. The tips16 are outer edges of the blades 13. A shortest distance RL1 measuredfrom an imaginary line L1 passing through the center A1 of the hub 11 toan end (front end) of the tip 16 close to the leading edge 14 is equalto a shortest distance RT1 measured from the imaginary line L1 to theother end (rear end) of the tip 16 close to the trailing edge 15.

However, the axial flow fan 10 of the related art has the followinglimitations.

First, the axial flow fan 10 generates noise during operation. Due tosuch noise, users complain about products using axial flow fans such asthe axial flow fan 10.

Thus, various design changes have been attempted to reduce noise of theaxial flow fan 10. In spite of such attempts, noise of the axial flowfan 10 is not sufficiently reduced, or the flowrate of air by the axialflow fan 10 is reduced if the noise of the axial flow fan 10 is reduced.

If the axial flow fan 10 is used in an outdoor unit of an airconditioner, the size of the axial flow fan 10 is limited preventinterference with other components disposed in the outdoor unit such asan orifice disposed in the outdoor unit for guiding air blown by theaxial flow fan 10. Therefore, it is necessary to modify componentsdisposed in the outdoor unit to increase the output power of the axialflow fan 10. That is, modification of components is necessary toincrease the flowrate of air blown by the axial flow fan 10.

SUMMARY

Embodiments provide an axial flow fan generating less noise and an airconditioner outdoor unit including the axial flow fan.

Embodiments also provide an axial flow fan configured to reduce noisewithout affecting the flow rate of air and an air conditioner outdoorunit including the axial flow fan.

Embodiments also provide an axial flow fan configured to increase theflow rate of air more easily and an air conditioner outdoor unitincluding the axial flow fan.

In one embodiment, an axial flow fan includes: a hub; and a plurality ofblades disposed on an outer surface of the hub, wherein each of theblades satisfies that a shortest distance measured from an imaginaryline (L2) passing through a center of the hub to a front end of an outeredge of the blade is different from a shortest distance measured fromthe imaginary line (L2) to a rear end of the outer edge of the blade,wherein the front end of the outer edge of the blade is a leading end ina rotation direction of the blade, and the rear end of the outer edge ofthe blade is a trailing end in the rotation direction of the blade.

In another embodiment, an axial flow fan includes: a hub; and aplurality of blades disposed on an outer surface of the hub, whereineach of the blades satisfies that when the blade is rotated, atrajectory formed by a front end of an outer edge of the blade isgreater than a trajectory formed by a rear end of the outer edge of theblade.

In another embodiment, there is provided an outer unit of an airconditioner, the outer unit including: a casing including a suction holeand a discharge hole for inflows and outflows of air; an outdoor heatexchanger disposed in the casing to allow a flow of refrigerant therein;an axial flow fan configured to blow outdoor air for heat exchangebetween the outdoor air and the refrigerant flowing in the outdoor heatexchanger; a motor configured to rotate the axial flow fan; and anorifice configured to guide outdoor air blown by the axial flow fan toan outside area of the casing through the discharge hole, wherein theaxial flow fan includes a blade, and the blade satisfies that a shortestdistance measured from an imaginary line (L2) passing through a centerof a hub of the blade to a front end of an outer edge of the blade isdifferent from a shortest distance measured from the imaginary line (L2)to a rear end of the outer edge of the blade, wherein the front end ofthe outer edge of the blade is a leading end in a rotation direction ofthe blade, and the rear end of the outer edge of the blade is a trailingend in the rotation direction of the blade.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features will be apparent fromthe description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawings will be provided by the Office upon request and paymentof the necessary fee.

FIG. 1 is a plan view illustrating an axial flow fan of the related art.

FIG. 2 is a schematic side view illustrating the axial flow fan of therelated art.

FIG. 3 is a plan view illustrating an axial flow fan according to anembodiment.

FIG. 4 is a schematic side view illustrating the axial flow fanaccording to the embodiment.

FIG. 5 is a view illustrating results of simulations for comparing thevelocity of air flows by the axial flow fan of the embodiment with thevelocity of air flows by an axial flow fan of the related art.

FIG. 6 is a view illustrating results of simulations for comparing thevelocity of turbulent flows of air by the axial flow fan of theembodiment with the velocity of turbulent flows of air by an axial flowfan of the related art.

FIG. 7 is a sectional view illustrating main parts of an air conditioneroutdoor unit to which the axial flow fan of the embodiment is applied.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, an axial flow fan will be described in detail according toan embodiment with reference to the accompanying drawings.

FIG. 3 is a plan view illustrating an axial flow fan 20 according to anembodiment, and FIG. 4 is a schematic side view illustrating the axialflow fan 20 according to the embodiment.

Referring to FIGS. 3 and 4, the axial flow fan 20 includes a hub 21 anda plurality of blades 23. The hub 21 has an approximately cylindricalshape. A rotation shaft (not shown) is coupled to the hub 21 to rotatethe axial flow fan 20. Substantially, the rotation shaft is coupled to acenter A2 of the hub 21. The blades 23 are disposed on the outer surfaceof the hub 21. Base on the rotation direction of the blades 23, theblades 23 include: leading edges 24; trailing edges 25; and tips 26forming outer edges of the blades 23. If the blades 23 are rotated, airflows in the direction of the rotation shaft.

A shortest distance measured from an imaginary line L2 passing throughthe center A2 of the hub 21 to a front end of the blade 23 is differentfrom a shortest distance measured from the imaginary line L2 to a rearend of the blade 23. That is, a shortest distance RL2 measured from theline L2 to a front end of the tip 26 close to the leading edge 24 isdifferent from a shortest distance RT2 measured from the line L2 to arear end of the tip 26 close to the trailing edge 25.

In detail, the shortest distance RL2 measured from the line L2 to thefront end of the tip 26 close to the leading edge 24 is greater than theshortest distance RT2 measured from the line L2 to a rear end of the tip26 close to the trailing edge 25. In other words, the distance betweenthe line L2 and the tip 26 is varied. That is, the distance between theline L2 and the tip 26 is gradually reduced from the front end to therear end of the tip 26.

Owing to this structure of the blade 23, when the blade 23 is rotated,the trajectory of the front end of the tip 26 may be different from thetrajectory of the rear end of the tip 26.

That is, according to the current embodiment, when the blade 23 isrotated, the diameter of a trajectory formed by a portion of the blade23 close to the leading edge 24 of the blade 23 may be different fromthe diameter of a trajectory formed by another portion of the blade 23close to the trailing edge 25 of the blade 23.

That is, according to the current embodiment, when the blade 23 isrotated, the diameter of a trajectory formed by a portion of the blade23 close to the leading edge 24 of the blade 23 may be greater than thediameter of a trajectory formed by another portion of the blade 23 closeto the trailing edge 25 of the blade 23.

That is, according to the current embodiment, when the blade 23 isrotated, the diameter of the trajectory of the blade 23 may be graduallyreduced in a direction from the front end of the tip 26 close to theleading edge 24 to the rear end of the tip close to the trailing edge25. In addition, the trajectory of the blade 23 formed by rotation ofthe blade 23 may have a cylindrical shape the diameter of which reducesgradually in the direction of air blown by the axial flow fan 20.

Hereinafter, effects of the axial flow fan 20 of the embodiment will bedescribed in detail with reference to the accompanying drawings.

FIG. 5 is a view illustrating results of simulations for comparing thevelocity of air flows by the axial flow fan 20 of the embodiment withthe velocity of air flows by an axial flow fan of the related art, andFIG. 6 is a view illustrating results of simulations for comparing thevelocity of turbulent flows of air by the axial flow fan 20 of theembodiment with the velocity of turbulent flows of air by an axial flowfan of the related art.

Referring to FIG. 5, flows of air by an axial flow fan is indicated byblue, green, yellow, and red colors. The velocity of flows of airincreases in the order of blue, green, yellow, and red. That is, asshown in FIG. 5, the velocity of flows of air by the axial flow fan ofthe embodiment is significantly greater than the velocity of flows ofair by an axial flow fan of the related. Numerically, the flow rate ofair blown by the axial flow fan of the embodiment is greater than theflow rate of air blown by the axial flow fan of the related art by about5%.

FIG. 6 illustrates turbulent flows of air by the axial flow fan of theembodiment and the axial flow fan of the related art. In FIG. 6, thevelocity of the turbulent flows of air is denoted by the same colors asthose used in FIG. 5. As shown in FIG. 6, the axial flow fan of theembodiment causes less turbulent flows as compared with the axial flowfan of the related art. Numerically, as compared with the axial flow fanof the related art, the axial flow fan of the embodiment reducesturbulent flows by about 3% and noise by about 2%.

Hereinafter, an explanation will be given on an exemplary case where theaxial flow fan 20 is used in an outdoor unit of an air conditioner.

FIG. 7 is a sectional view illustrating main parts of an air conditioneroutdoor unit 100 in which the axial flow fan 20 of the embodiment isused.

Referring to FIG. 7, a casing 110 forms the exterior of the airconditioner outdoor unit 100. A suction hole 111 is formed in the rearside of the casing 110, and a discharge hole 113 is formed in the frontside of the casing 110. Various components of a heat exchanger aredisposed in the casing 110.

For example, an outdoor heat exchanger 120 and a compressor 130 aredisposed in the casing 110. Refrigerant flowing in the outdoor heatexchanger 120 exchanges heat with outdoor air, and the compressor 130 isused to compress the refrigerant. In addition, the axial flow fan 20 anda motor 140 are disposed in the casing 110. The axial flow fan 20 isrotated by the motor 140 to blow outdoor air for facilitating heatexchange between the air and the refrigerant flowing in the outdoor heatexchanger 120. In detail, as the axial flow fan 20 is rotated, air isintroduced into the casing 110 through the suction hole 111 anddischarged from the casing 110 through the discharge hole 113 after theair exchanges heat with the outdoor heat exchanger 120.

As described above, in the axial flow fan 20, the shortest distancemeasured from the imaginary line L2 passing through the center A2 of thehub 21 to the front end of the blade 23 may be different from theshortest distance measured from the imaginary line L2 to the rear end ofthe blade 23. That is, when the axial flow fan 20 is rotated, thetrajectory of the front end of the tip 26 may be different from thetrajectory of the rear end of the tip 26.

An orifice 150 is provided in the casing 110. The orifice 150 has anapproximately ring shape. The orifice 150 guides air blown by the axialflow fan 20 to the outside of the casing 110 through the discharge hole113. For this, the orifice 150 is disposed at the downstream side of theaxial flow fan 20 in a direction in which air flows by the axial flowfan 20. That is, the orifice 150 is closer to the trailing edges 25 ofthe blades 23 of the axial flow fan 20 than the leading edges 24 of theblades 23 of the axial flow fan 20. The orifice 150 is overlapped withportions of the blades 23. That is, the orifice 150 is overlapped withthe trailing edges 25 of the blades 23.

The output power of the axial flow fan 20 (that is, the flow rate of airblown by the axial flow fan 20) may be proportional to the size of theblades 23. Since the orifice 150 are close to the trailing edges 25, ifthe size of the trailing edges 25 of the blades 23 is increased toincrease the size of the blades 23, components including the orifice 150have to be redesigned. In other words, if the shortest distance RT2 fromthe imaginary line L2 passing through the center of the axial flow fan20 to the rear end of the tip 26 of the blade 23 close to the trailingedge 25 is increased, it may be necessary to redesign components of theoutdoor unit 100.

However, according to the embodiment, the size of the blade 23 can beincreased by increasing the leading edge 24 of the blade 23 that isdistant from the orifice 150, and thus it may be unnecessary to redesignthe orifice 150. That is, the output power of the axial flow fan 20 canbe increased by increasing the shortest distance RL2 from the imaginaryline L2 to the front end of the tip 26 close to the leading edge 24without having to redesign components of the outdoor unit 100.

According to the embodiments, the axial flow fan and the air conditioneroutdoor unit including the axial flow fan provide the following effects.

Owing to the above-described shape of the blade, noise can be reducedwhile increasing the flow rate of air.

In addition, noise of the axial flow fan can be reduced and the flowrate of air blown by the axial flow fan can be increased without havingto redesign other components of the outdoor unit.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. An axial flow fan comprising: a hub; and a plurality of bladesdisposed on an outer surface of the hub, wherein each of the bladessatisfies that a shortest distance measured from an imaginary line (L2)passing through a center of the hub to a front end of an outer edge ofthe blade is greater than a shortest distance measured from theimaginary line (L2) to a rear end of the outer edge of the blade,wherein the front end of the outer edge of the blade is a leading end ina rotation direction of the blade, and the rear end of the outer edge ofthe blade is a trailing end in the rotation direction of the blade. 2.The axial flow fan according to claim 1, wherein each of bladescomprises a leading edge in the rotation direction thereof, a trailingedge in the rotation direction thereof, and a tip as the outer edge,wherein a shortest distance (RL2) measured from the imaginary line (L2)passing through the center of the hub to a front end of the tip close tothe leading edge is greater than a shortest distance (RT2) measured fromthe imaginary line (L2) to a rear end of the tip close to the trailingedge.
 3. The axial flow fan according to claim 2, wherein a shortestdistance from the imaginary line (L2) to the tip is gradually decreasedin a direction from the front end of the tip close to the leading edgeto the rear end of the tip close to the trailing edge.
 4. The axial flowfan according to claim 1, wherein the hub has a cylindrical shape. 5.The axial flow fan according to claim 1, further comprising a rotationshaft coupled to the hub for rotating the axial flow fan.
 6. The axialflow fan according to claim 5, wherein the rotation shaft is coupled tothe center of the hub.
 7. The axial flow fan according to claim 5,wherein if the blades are rotated, air is forced to flow along therotation shaft.
 8. An axial flow fan comprising: a hub; and a pluralityof blades disposed on an outer surface of the hub, wherein each of theblades satisfies that when the blade is rotated, a trajectory formed bya front end of an outer edge of the blade is greater than a trajectoryformed by a rear end of the outer edge of the blade.
 9. The axial flowfan according to claim 8, wherein each of blades comprises a leadingedge in a rotation direction thereof, a trailing edge in the rotationdirection thereof, and a tip as the outer edge, wherein when the bladeis rotated, the diameter of a trajectory formed by a portion of theblade close to the leading edge is greater than the diameter of atrajectory formed by another portion of the blade close to the trailingedge.
 10. The axial flow fan according to claim 9, wherein the diameterof a trajectory formed by rotation of the blade is gradually reduced ina direction from a front end of the tip close to the leading edge to arear end of the tip close to the trailing edge.
 11. The axial flow fanaccording to claim 8, wherein a trajectory formed by rotation of theblade has a cylindrical shape with a diameter gradually reducing in adirection of air blown by the axial flow fan.
 12. An outer unit of anair conditioner, the outer unit comprising: a casing comprising asuction hole and a discharge hole for inflows and outflows of air; anoutdoor heat exchanger disposed in the casing to allow a flow ofrefrigerant therein; an axial flow fan configured to blow outdoor airfor heat exchange between the outdoor air and the refrigerant flowing inthe outdoor heat exchanger; a motor configured to rotate the axial flowfan; and an orifice configured to guide outdoor air blown by the axialflow fan to an outside area of the casing through the discharge hole,wherein the axial flow fan comprises a blade, and the blade satisfiesthat a shortest distance measured from an imaginary line (L2) passingthrough a center of a hub of the blade to a front end of an outer edgeof the blade is different from a shortest distance measured from theimaginary line (L2) to a rear end of the outer edge of the blade,wherein the front end of the outer edge of the blade is a leading end ina rotation direction of the blade, and the rear end of the outer edge ofthe blade is a trailing end in the rotation direction of the blade. 13.The outdoor unit according to claim 12, wherein the orifice is locatedat downstream side of the axial flow fan in a direction in which airflows by the axial flow fan.
 14. The outdoor unit according to claim 12,wherein the orifice is overlapped with a portion of the blade close to atrailing edge of the blade.
 15. The outdoor unit according to claim 12,wherein the orifice has a ring shape.
 16. The outdoor unit according toclaim 12, further comprising a compressor configured to compress therefrigerant.
 17. The outdoor unit according to claim 12, wherein thesuction hole of the casing is formed in a rear side of the casing tointroduce outdoor air into the casing.
 18. The outdoor unit according toclaim 12, wherein the discharge hole of the casing is formed in a frontside of the casing to discharge outdoor air from the casing after theoutdoor air exchanges heat with the refrigerant flowing in the outdoorheat exchanger.